Abstract

A pulsed or "triggered" instability occurs when pressure
oscillations develop in a linearly stable combustion
system after being subjected to a sufficiently
large disturbance. Such true nonlinear instabilities
usually occur as subcritical bifurcations in dynamical
systems theory. Understanding which nonlinear
processes can lead to subcritical bi~urcations is
the focus of this work. Earlier work with the approximate
analysis used here has shown convincingly
that nonlinear acoustics alone does not contain the
phenomenon of pulsed instabilities; evidently some
other nonlinear contribution must also be included.
An extensive experimental and numerical investigation
conducted by Baum and Levine strongly suggests
that nonlinear combustion is required. Using
models of pressure and velocity coupling, the current
work studies the effect of nonlinear combustion
on the behavior of the system.